This invention relates to an hydraulic machine. In one application, the invention relates to a cleaner for cleaning a submerged surface, such as the submerged portion of a swimming pool.
Numerous swimming pool cleaners have been proposed, which fall into two main categories. The first category includes pool cleaners which use an oscillating valve element such as a "hammer" valve or a flexible diaphragm which alternately constricts and relaxes, to interrupt a flow of liquid through the pool cleaner repetitively, thus developing forces which propel the pool cleaner in one direction or another. The second category of pool cleaners includes those which employ a turbine or the like which is operated by a flow of water through the pool cleaner, the turbine in turn driving feet, wheels, tracks or another drive mechanism. Generally speaking, although pool cleaners in the first category are mechanically simple, they tend to impose a greater amount of stress on the pool filtration unit and pump due to the repetitive shock waves generated by their action. Pool cleaners of the second category do not produce such shock waves, but tend to be more complicated mechanically than those in the first category.